The present invention relates to a battery apparatus for driving a motor that drives a vehicle such as automobile, and more particularly to a battery apparatus including a temperature sensor for detecting the temperature of the battery.
Since a battery apparatus for automobile is charged and discharged with large amounts of current, the temperature of the secondary battery may rise to relatively high depending on the condition of use. For this reason, it is necessary to detect the temperature of the secondary battery for controlling the charging and discharging. For achieving this, conventional battery apparatuses for vehicle have a PTC which serves as a temperature sensor attached to the surface of a battery module made up of serially connected secondary batteries. In the PTC, when the temperature of the battery exceeds a preset temperature, electric resistance thereof dramatically increases. The PTC is attached to the surface of each secondary battery, and serially connected with each other. The above battery module draws a lead wire for the temperature sensors connected with the PTCs.
The temperature sensor such as PTC fixed to the surface of the battery module is able to detect the secondary battery with accuracy. However, in the process of producing the battery module, a temperature sensor is fixed to the surface of every secondary battery, and lead wires of the respective temperature sensors are connected in serial, resulting in a drawback that the production of the battery module takes a lot of labor. In addition, since the temperature sensors are fixed to the battery module, the cost for producing the battery module increases. In addition, the battery module needs to be replaced when the secondary battery breaks down. At this time, it is impossible to replace only the secondary battery, but the temperature sensor should be replaced together, which leads a drawback that the repairing cost increases.
This drawback can be eliminated by disposing a temperature sensor to a casing which fixes the battery module. However, it takes a lot of labor to dispose a temperature sensor to a casing which accommodates a plurality of battery modules so as to enable accurate detection of the temperature of each secondary battery. Furthermore, there is another drawback that it is difficult to allow each temperature sensor to access to the surface of the secondary battery with accuracy.
The present invention was devised to solve the above-mentioned drawbacks. It is an important object of the present invention to provide a battery apparatus for vehicle in which a plurality of temperature sensors can be disposed in close to the respective secondary batteries so that accurate detection of temperature can be achieved readily and easily.